Two-cycle double-acting engine



Sept. 25, 1951 1.. WILKINS TWO-CYCLE DOUBLE ACTING ENGINE 2 Sheets-Sheet 1 Filed Feb. 18 1950 INVENTOR. Baez-7 A. Wax/ms, Y wf% fi firm/a 5/;

Patented Sept. 25, 1951 UNITED STATES PATENT OFFICE TWO-CYCLE DOUBLE-ACTING ENGINE Robert L. Wilkins, Indianapolis, Ind.

Application February 18, 1950, Serial No. 144,945

, Claims. 1 This invention relates to a dual acting internal combustion engine.

The chief object of the present invention is to provide a simple, compact engine structure that is symmetrical and wherein oppositely disposed parts are substantially identical.

One feature of the invention resides in utilizing the piston rod as a valve control.

A second feature of the invention resides in duplicating certain of the parts.

A third feature of the invention resides in pro-- viding a single piston Within a cylinder and arranging same so that for any given fuel setting the force of the explosion is the same, that is, the unit force exerted upon the opposite faces of the piston by successive explosions is equal.

As indicated above, the present invention, like similar acting two-cycle dual engines, provides a power'impulse for each movement of the power piston.

Other objects and features of the invention will be set forth in greater detail hereinafter.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

In the drawings:

Fig. 1 is a central sectional view througha single cylinder embodiment of the invention.

Fig. 2 is a sectional view through an electrically controlled valve embodiment.

Fig. 3 is a vertical sectional view of a modified form of the invention wherein the piston rod, while utilized for valve control extends through but one of the cylinder heads.

Fig. 4 is a similar view of a similar but further modified form, the modification herein comprising an internal coolant control, also piston rod operable.

In Fig. 1 of the drawings, ll indicates a cylin der water jacketed at I I. This is suitably and detachably supported by crank case l2 having guide way I 3 therein for slidable accommodation ofcrosshead H. To the same is pivotally connected at l5 one end of connecting rod It, the

other end of which is pivotally carried by crank portion I! of crank shaft I8 suitably supported in crank case bearings such as schematically illustrated at I9. A pan 2| closes the case.

The upper end of cylinder II has suitably attached thereto upper head 2| water jacketed at 22. The lower end of cylinder [0 has suitably attached thereto in depending relation lower head 23 water jacketed at 24. These heads are identical so a description of one will suffice for both.

Each head includes an intake passage 25 for 2 connection to a suitable fuel supply source not shown. Poppet valve 26 controls the intakeand has stem 21 projecting outwardly and mounting closing spring 28 retained on and concentric with said stem by retainer 29 of any suitable character.

The head includes the firing chamber 3| and the spark plug 3| is mounted in the head opening 32 provided for that purpose. The head also includes the piston rod bore 33 provided with rings 34 for sealingthe rod 35.

Herein rod 35 extends through the opposed heads and intermediately has suitably secured to it the double acting piston 36 mounting rings 31. The cylinder midway between its ends includes the exhaust ports 38 leading into the exhaust manifold 39. This may extend'entirely around the cylinder and the exhaust ports may be similarly disposed, if desired.

The electrical circuit to the plugs is omitted for clearness but each plug is energized at the proper time. Carried by each end of the piston rod 35 is a valve actuating arm 40. The crosshead [4 is suitably attached to the lowerend of said rod 35.

Operation is as follows: When the piston un-' covers the exhaust ports that end of the cylinder then communicating therewith exhausts the previously burned gases. At this time, or slightly before, depending on the length of the piston, the intake valve at the opposite end of the cylinder opens and supplies that end with fuel and air. As the piston continues its travel the first end of the cylinder through the piston continues to exhaust and the other end of the cylinder compresses the fuel and air, the intake valve thereto previously having closed. When this charge is compressed it is fired and the piston reverses its travel. The said first mentioned end of the cylinder is then charged as soon as exhaust ports are closed and the charge in said first end is then compressed and fired. If scavenging is desired the intake valves may be opened before the exhaust ports are closed. The expanded burned gases in said second end are exhausted as soon as the exhaust ports are uncovered by the piston and communicate with that end of the cylinder.

Hence for each stroke of the piston there is a power application to rod 35 and hencethe rod is. alternately subjected to a push and pull force which is equal because the rod extends through each head.

Reference will now be had to Fig. 2. Inthis form of the invention each valve is spring closed as before but herein the valve is opened by a solenoid suitably energized and controlled by switch means. Such switch means may have an active element carried by rod for bridging contact to close and open the circuit to the solenoid. If preferred the valves may be solenoid controlled through a timing distributor similar to that utilized for energizing the plugs in timed relation.

In the form shown in Fig. 2 the piston rod I35 mounts upon the exposed portions elongated contact bridging portions I50. These twice bridge contacts I5I and I52 and close the circuit between lines I53 and I54. Disposed adjacent rod I35 and in the path of member I50 is a tiltable normally closed switch I55 connected in series with the aforesaid switch. Associated with the tiltable switch is a dashpot I55 and spring I51. The aforesaid is duplicated at opposite ends of the rod. The switch control at one end controls the solenoid I40 at the opposite end and in turn opens valve I26 constrained to closed position by spring I28. Stem I21 mounts core I58.

Operation is as follows: At the predetermined time that the intake valve is to open switch I55 is closed and rod movement disposes portion I50 across contacts [El and I52 to energize solenoid I58 to hold open the intake valve. Upon termination of intake duration this switch opens and stays open until the end of the piston stroke.

During this interval the intake valve is closed.

Upon attainment of the end of the stroke member I5Il opens switch I55 in opposition to spring I51. Upon return stroke, while spring I51 tends to close switch I 55 the dashpot holds it open until member I50 passes beyond contacts I53I54. Thus selective control of the solenoids is attained.

When the aforesaid balanced type of structure is not desired or required, a crank shaft rotatable timer switch can be employed and successively energize the solenoids at predetermined times and for predetermined intervals.

In Fig. 3 there is illustrated a modified form wherein 236 indicates the piston with rings 231 slidable in the cylinder 2H]. The heads 22f and 224 are not identical but are similar. Herein stem 235 mounts arm 24!) terminating in an angular end 240 mounting a roller 260.

Mounted upon two fixed pivots 26I and 262 are rockers 253 and 264 respectively. Rocker 253 actuates stem 221 of lower valve 226, while rocker 264 actuates stem tappet rod 265 that actuates stem 221 of upper valve 225. Each rocker arm includes an angularly disposed free end 263 and 264 mounting rollers 263 and 254* respectively.

In the reciprocation of stem 235 roller 260 engages rollers 283 and 254 and vice versa. Upon the down stroke, see 3, rocker 253 is rocked Clockwise for lower valve opening and rocker 254 is rocked clockwise which i without function. Upon the upward stroke rocker 2 54 is rocked counter-clockwise for upper valve opening and rocker 263 is similarly rocked without functioning. The position of pivots 25I-262 can be adjusted up or down or towards or away from each other for proper valve timing.

Reference will now be had to Fig. 4 wherein a slightly modified form of the preceding type is illustrated. Numerals utilized herein are of the three hundred series. In this form piston rod 235 as before mounts valve control actuator 340 with angular end 3 53 carrying roller 360.

Herein the lower and upper heads include auxiliary intake passages 310 each arranged to be connected to a pressure source of coolant such as compressed air, water, mist, steam or the like. Each is controlled by valve 31I carried by stem 312 associated with valve closing spring 313 as shown.

The lower auxiliary intake valve is directly actuated by member 340 engaging lower valve stem 312 to open the lower auxiliary intake when the piston is near the upper end of the stroke. The lower end of the cylinder is cooled and scavenged.

When the piston approaches the lower end of the cylinder 3I0, the arm 340 engages an angular end of tappet rod 314 and said rod is lowered to open upper auxiliary intake valve 31I for similarly cooling and scavenging the upper end of cylinder 3). In this form of the invention the ignition plugs are disposed centrally between the intake valves in each head but to one side thereof if necessary for clearance.

Operation of all forms of the invention are essentially the same except where noted hereinbefore. This invention, if desired, may be readily adapted to diesel type operation whenever desired.

While the invention has been illustrated and described in great detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character.

The several modifications described herein as well as others which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of the invention reference being had to the appended claims.

The invention claimed is:

1. In a dual acting, two-cycle engine having an elongated cylinder and a single piston therein, the combination of two heads closing opposite open ends of said cylinder, a piston rod connected to the piston, a connecting rod having crank connection to the engine crank shaft, an intake poppet valve in each head, common exhaust valve porting disposed approximately mid-way between the open ends of the cylinder, the piston being reciprocable beyond said porting and towards each of the heads for power impulse application to the crank shaft for each stroke of the piston, and means operable by the rod for selective actuation of said valves, said means comprising a solenoid for each valve, and switch means selectively controlling said solenoids, active elements of said means being movable by said rod.

2. An engine as defined by claim 1 wherein said switch means is of dual character, each of said dual portions comprising a pair of series connected switches, one being twice closable in rod reciprocation and the other being normally closed and rod opened, and means delaying closure of said other switch until said one switch has been closed and opened for the second time by said rod.

3. In a dual acting, two-cycle engine having an elongated cylinder, and a single piston reciprocable therein, the cylinder having exhaust porting equidistant from the ends, the combination of heads closing opposite ends of the cylinder, a rod for said piston and passable through at least one of the heads, an intake valve in each head and normally constrained to closed position, a rocker arm for opening each valve, and a single means reciprocable by said rod in the movement thereof and having dual contact with each of the rocker arms, but one of such contacts being effective for valve opening purposes.

4. In an engine as defined by claim 3 an auxiliary valve in each head normally constrained 6 to closed position and for the purpose described, REFERENCES CITED independent actuators for each auxiliary valve, The following references are of record in the and a. single means for actuating the actuators file of this patent: selectively near the ends of the piston stroke and carried by said rod 5 UNITED STATES PATENTS 5. An engine as defined by claim 3 wherein said Number Name Date last mentioned single means and the first men- 748,959 Korting Jan. 5, 1904 tioned single means are the same element. 858,280 Von Handorfi June 25, 1907 1,204,447 Jahnke Nov. 14, 1916 ROBERT L. WILKINS. 10 

